Francis paid Simpkins more than $150,000 for his help in getting lucrative contracts for his firm to provide "husbanding" services to Navy ships in Asia-Pacific ports, according to an indictment.

Simpkins was also provided with prostitutes when he stayed at the Hilton Hotel in Singapore, the indictment alleges. He had emailed Francis to make sure the prostitutes were disease-free, according to the indictment.

Seven of the nine people have pleaded guilty: Francis; a Navy captain; a commander; a retired lieutenant commander; an enlisted sailor; an ex-Naval Criminal Investigative Service agent, and a cousin of Francis' who worked for his company. All await sentencing in San Diego federal court.

A second commander has pleaded not guilty.

Simpkins was arrested at his home in Virginia. Prosecutors have asked a federal judge there to have him sent to San Diego for trial.

For more than two decades, Francis' firm supplied water, fuel, food, garbage and waste removal, tugboats, fenders and other items for Navy ships. Amid the scandal, the Navy has canceled all contracts with the firm.

Among the bribes, prosecutors say, were first-class airfare and hotel accommodations, Cuban cigars, entertainment tickets, expensive furnishings and the services of prostitutes. To accomodate Francis' company, ships were redirected to ports where the company was strong.

In 2010, Navy officials became suspicious that some of the bills submitted by Francis' firm from Thailand were padded.

Prosecutors said the bribery scheme cost taxpayers $20 million for bills that were padded and, in some cases, included payment for services not provided. The cost of lavish parties thrown by Francis for Navy officers was often hidden in the bills, prosecutors said.

"The investigation is far from over," said Andrew Traver, director of the Naval Criminal Investigation Service. "NCIS will follow the evidence wherever it leads."